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The usual state of oxygen and hydrogen: they are gases at room temperature.
Wiki User
∙ 12y ago
Wiki User
∙ 11y agoThe question is kind of like asking, "Is oxygen normally found as a gas, liquid, or solid?"
And the answer is that the standard state of oxygen is gas.
Wiki User
∙ 6y agoThe chemical symbol of oxygen is O. The molecule is O2.
Wiki User
∙ 6y agoO2
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What is the standard heat of formation of a free element in its standard state?
standred
Enthalpy changes accompanying a change of state are than those accompanying the heating of a substance at each state?
Any change of state involve a change of the system enthalpy.
What is one reason to use Hess's law?
Because enthalpy is a state function and an extensive property.
What is oxygen's physical state?
oxygen's physical state is gas
What is the usual state of oxygen and?
Oxygen is a gas.
What is the basic difference between enthalpy of formation?
Standard Heat (Enthalpy) of Formation, Hfo, of any compound is the enthalpy change of the reaction by which it is formed from its elements, reactants and products all being in a given standard state.By definition, the standard enthalpy (heat) of formation of an element in its standard state is zero, Hfo = 0.Standard Molar Enthalpy (Heat) of Formation, Hmo, of a compound is the enthalpy change that occurs when one mole of the compound in its standard state is formed from its elements in their standard states.Standard Enthalpy (Heat) of Reaction, Ho, is the difference between the standard enthalpies (heats) of formation of the products and the reactants.Ho(reaction) = the sum of the enthalpy (heat) of formation of products - the sum of the enthalpy (heat) of formation of reactants: Ho(reaction) = Hof(products) - Hof(reactants)To calculate an Enthalpy (Heat) of Reaction:Write the balanced chemical equation for the reaction Remember to include the state (solid, liquid, gas, or aqueous) for each reactant and product.Write the general equation for calculating the enthalpy (heat) of reaction: Ho(reaction) = Hof(products) - Hof(reactants)Substitute the values for the enthalpy (heat) of formation of each product and reactant into the equation. Remember, if there are 2 moles of a reactant or product, you will need to multiply the enthalpy term by 2, if molar enthalpies (heats) of formation are used.Standard Enthalpy (Heat) of FormationExample: Standard Enthalpy (Heat) of Formation of WaterThe standard enthalpy (heat) of formation for liquid water at 298K (25o) is -286 kJ mol-1. This means that 286 kJ of energy is released when liquid water, H2O(l), is produced from its elements, hydrogen and oxygen, in their standard states, ie, H2(g) and O2(g).This reaction is written as:H2(g) + ½O2(g) -----> H2O(l) Hfo = -286 kJ mol-1The standard enthalpy (heat) of formation of water vapour at 298K (25o) is -242 kJ mol-1.This means that 242 kJ of energy is released when gaseous water (water vapour), H2O(g), is produced from its elements, hydrogen and oxygen, in their standard states, ie, H2(g) and O2(g).This reaction is written as:H2(g) + ½O2(g) -----> H2O(g) Hfo = -242 kJ mol-1
What best describe the enthalpy of formation of a substance?
The enthalpy of formation of a substance is the amount of energy that was put in or evolved from the making of that substance from the individual elements.
What is the standard enthalpy of formation of hydrogen bromide?
[from wikipedia] The standard enthalpy of formation"standard heat of formation" of a compound is the change of enthalpy that accompanies the formation of 1 mole of a substance in its standard state from its constituent elements in their standard states (the most stable form of the element at 1 bar of pressure and the specified temperature, usually 298.15 K or 25 degrees Celsius). Its symbol is ΔHfO.
What is the stable state of an element?
The standard state, or reference state, of an element is defined as its thermodynamically most stable state at 1 bar at a given temperature (typically at 298.15 K). In thermochemistry, an element is defined to have an enthalpy of formation of zero in its standard state. For example, the reference state for carbon is graphite, because it is more stable than the other allotropes.
What do the symbols mean Delta Hr Hf Hc Hn Ha in chemistry btw i know theyre enthalpy changes?
delta Hr is the enthalphy change of a reaction delta Hf is the enthalpy of formation where one mole of a substance is formed ( generally in its naturally occurring physical state) delta Hc is the enthalpy of combustion where one mole of a substance in its standard state undergoes combustion delta Hn is the enthalpy of neutralization where one mole of H+ reacts with OH- to form one mole of H2O delta Ha is the enthalpy of atomization where a molecule splits to form its neutral atomic components
What is the standard heat of formation of a free element in its standard state?
standred
Why is the standard enthalpy formation of oxygen zero?
As for every pure element, the heat of formation of O is zero. That is because elements are the smallest constituents and are not made up of anything; therefore, no heat is needed to form pure elements from base substances, as there are no base substances to be used to form the pure elements.
Is enthalpy a state function?
Yes it is state function
What is standard enthalpy change of atomization?
the breaking down of elements into atoms. it is the energy required when 1 mole of a substance completely decomposes into its gaseous atoms i.e endothermic reaction, delta H is +ve meaning breaking bonds
What is the relationship between enthalpy and temperature?
Enthalpy is the amount of energy in a system and when this changes (when a reaction happens), the energy is either released (exothermic) or absorbed (endothermic) and this energy is usually released or absorbed as heat. Therefore when the enthalpy decreases, heat is released from the system making it exothermic. In contrast, when the enthalpy increases, heat is absorbed making it endothermic.
Enthalpy changes accompanying a change of state are than those accompanying the heating of a substance at each state?
Any change of state involve a change of the system enthalpy.
How do forces of enthalpy determine change?
Firstly enthalpy is NOT a force; rather it is a state variable - a property of a reaction. To understand how forces affect enthalpy such that a change in state is observed - that is what you wanted to say. Secondly, ice formation is a good example of explaining enthalpy changes. As water - a relatively expanded form with a level of "heat" i.e. from interactions between water molecules - freezes to ice, that heat is given off into the environment; a measure of heat of the system has been lost to the environment and subsequently the enthalpy of the system has changed. With less heat - energy relating to molecular interactions - there are less molecular interactions and as a result the water molecules move closer together and thus ice forms. Indeed this is one way in which a change in enthalpy (NOT a force) affects a change in state. I do hope this was not so late so that I have wasted my time.
